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Institution

DECHEMA

NonprofitFrankfurt am Main, Germany
About: DECHEMA is a nonprofit organization based out in Frankfurt am Main, Germany. It is known for research contribution in the topics: Corrosion & Oxide. The organization has 756 authors who have published 1307 publications receiving 25693 citations.
Topics: Corrosion, Oxide, Coating, Alloy, Catalysis


Papers
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Journal ArticleDOI
TL;DR: The data show that daily fluctuations can only be observed in the MFC performance at WWTPs below 50,000 population equivalents, and the effect of environmental conditions on the current densities was evaluated.
Abstract: Microbial fuel cells (MFCs) are often discussed as a part of a sustainable generation of electricity for the coming ‘energy revolution’. In particular, the application of MFCs in wastewater treatme...

11 citations

Journal ArticleDOI
TL;DR: A novel cyanobacterial α dioxygenase from Crocosphaera subtropica was heterologously expressed in E. coli and applied for the biotechnological production of C11 - C15 branched-chain fatty aldehydes, which exhibited green-soapy, sweety odors with partial citrus-like, metallic, peppery, and savory-tallowy nuances.
Abstract: As a result of their pleasant odor qualities and low odor thresholds, iso- and anteiso-fatty aldehydes represent promising candidates for applications in flavoring preparations. A novel cyanobacter...

11 citations

Journal ArticleDOI
TL;DR: In this article, a study of the erosion-corrosion resistance of uncoated and aluminized 12% chromium steel in a fluidized-bed rig is reported, with spallation of scale being the primary mechanism of material wastage.
Abstract: In this paper, some results from a study of the erosion-corrosion resistance of uncoated and aluminized 12% chromium steel in a fluidized-bed rig are reported. The aims of the research are to establish and compare the erosion-corrosion resistance of these materials for possible applications as heat exchangers in future power plants, and to obtain an increased understanding on their behaviour and mutual superiority in a range of conditions. Damage to the uncoated 12% chromium steel occurs by an oxidation-affected erosion process under all the studied conditions, with spallation of scale being the primary mechanism of material wastage. At a temperature of 550 °C, the uncoated steel follows the typical angle-dependence of a brittle material, while, at temperatures above 550 °C, it follows an angle-dependence that is more typical of a ductile material. This change in the angle-dependence with temperature is related to characteristics, i.e. uniformity, adhesion and density, of the formed oxide scales. The rate of material wastage increases with increase in speed and temperature, due to the development of thicker, more uniform and more dense oxide scales, that promote more severe scale spallation. The erosion-corrosion behaviour of the aluminized 12% chromium steel changes in the temperature range from 600°C to 650 °C. This is due to a shift from a brittle-like to a ductile-like angle-dependence and to a more rapid oxide scale build-up at temperatures above 600 °C. At an impact angle of 30° and at 550 °C and 600 °C, the prevailing erosion-corrosion process for the aluminized steel is oxidation-affected erosion. At 650 °C and 700 °C for an impact angle of 90°, the primary erosion-corrosion mode is essentially erosion-enhanced oxidation. The results of the study have also demonstrated that the Al 5 Fe 2 coating deposited by pack aluminization offers enhanced protection against erosion-corrosion at shallow impact angles at 550 °C and 600 °C and at steeper impact angles at 700 °C.

11 citations

Journal ArticleDOI
Abstract: The oxidation resistance of TiAl-alloys can be improved by several orders of magnitude by treating the surface of the materials with small amounts of halogens especially Cl and F. The oxidation mechanism changes due to the so called halogen effect. The formation of a fast growing mixed oxide scale on untreated alloys is suppressed, instead a thin protective alumina scale is formed on samples after optimum treatment. The different methods only influence the surface region of the components so that the bulk properties are not affected. Recent results achieved with complex TiAl-samples showed the potential that the fluorine effect could be used for TiAl-components in several high temperature applications e.g. jet engines. TiAl-specimens were treated with fluorine and chlorine in several ways and their performance during high temperature oxidation tests in air was investigated. Results of isothermal and thermocyclic oxidation tests are presented. The long term stability of the fluorine effect lasted for at least one year under thermocyclic exposure at 900°C in laboratory air. The results are discussed in terms of later use of the fluorine effect for technical applications.

11 citations

Journal ArticleDOI
TL;DR: The alcohol dehydrogenase from Lactobacillus brevis was successfully used for the reductive synthesis of enantiopure secondary aliphatic alcohols and the cofactor utilisation turned out to be very high and a TON NADP + was easily achievable for both 2-heptanone and 2-octanone by substrate coupled cofactor regeneration with excess of 2-propanol.
Abstract: Biphasic reactions offer an attractive alternative for the utilisation of enzymes for conversion of hardly water soluble substrates. Especially, the alcohol dehydrogenase from Lactobacillus brevis was successfully used for the reductive synthesis of enantiopure secondary aliphatic alcohols. With the enzymatic catalyst and the cofactor effectively retained in the reactive aqueous phase, the continuous operation was demonstrated by continuous addition and withdrawal of the non-reactive phase. The four tested substrates 2-heptanone, 2-octanone, 2-nonanone, and 2-decanone showed that the space time yield and turnover numbers (TON) of the enzyme decrease as the availability of the substrate decreases with increasing partition coefficients. Nevertheless, a TONLbADH of up to 478 × 103 could be achieved. Remarkably, the cofactor utilisation turned out to be very high and a TON NADP + of more than 20 × 103 was easily achievable for both 2-heptanone and 2-octanone by substrate coupled cofactor regeneration with excess of 2-propanol.

11 citations


Authors

Showing all 760 results

NameH-indexPapersCitations
Wolf B. Frommer10534530918
Michael W. Anderson10180863603
João Rocha93152149472
Martin Muhler7760625850
Michael Hunger6029511370
Ivars Neretnieks442247159
Michael Schütze403436311
Jens Schrader381294239
Roland Dittmeyer312063762
Lei Li291984003
Dirk Holtmann291073033
Lasse Greiner26741994
Klaus-Michael Mangold23571590
A. Rahmel23591967
Gerhard Kreysa22781305
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
20227
202145
202053
201949
201844